Characterizing Thermal Properties in Energy Research

ECN TECHNOLOGY DAY – THERMAL ANALYSIS

FEBRUARY 5TH, 2015

ADAM HARRISMANAGING DIRECTOR

Characterizing Thermal Properties inEnergy Research

AGENDA• Who we are?• What we do?• Understanding MTPS Method:

Modified Transient Plane Source• Application Examples:

• Metal Hydrides• Thermoelectrics

• Q&A

WHO WE ARE

C-THERM TECHNOLOGIES LTD.

Non-destructive, thermalsensor technology solutions forR&D, QC and productionapplications - delivering fast,accurate measurement ofthermal conductivity andeffusivity in seconds.

WINNER

WHAT WE DO?

PRODUCT LINES

THERMAL CHARACTERIZATIONC-Therm TCi™ Thermal Conductivity AnalyzerClients include:

• NRC • Philip Morris• Henkel Tech. • Huntsman• Kodak • US Air Force

PHARMACEUTICAL APPLICATIONSC-Therm ESP™ Effusivity Sensor SystemClients include:

• Patheon • Astra Zeneca• Wyeth • Biovail• BMS • USP

NEW DILATOMETER

TEMPERATURE RANGE Room Temperature to 1600°C

TEMPERATURE RESOLUTION 0.1°C

MAX DISPLACEMENT 4mm

ΔI RESOLUTION 1.25 nm/digit

ATMOSPHERE Air, Vacuum, Inert Gas

SAMPLE DIMENSIONS 10 to 50mm long x max φ 12mm

SAMPLE HOLDER Fused Silica, Alumina

CONFIGURATIONS Single or Dual LVDT System1200°C or 1600°C

HEATING ELEMENT Kanthal Wire, SiC

Rate of Increase (°C) > 50°C/min

TCi PROPERTY ANALYZERThermal Conductivity Range0 to 500 W/mK

Thermal Effusivity Range5 to 40,000 Ws½/m²K

No Sample PreparationUnlimited sample sizes

Non-DestructiveLeaves sample intact

VersatileTests solids, liquids, powders & pastes

Highly FlexibleDesigned for lab, QC & at-line testing

AccuracyBetter than 5%

PrecisionBetter than 1%

Temperature Range-50˚ to 200˚C

The C-Therm TCi measures two thermal properties primarily:

It also indirectly measures (calculated) Thermal Diffusivity andHeat Capacity and has user input capabilities to determine Density

What Does It Measure?

How Does It Work?Wood feels warm

Metal feels cold

Heat always flows from a hot object to a cold object.

Wood is not a good conductor of heat, so it is slow toabsorb the heat.

Metal has higher “thermal conductivity” so the heatfrom your hand flows into the metal quickly - creatingthe sensation of it being cold.

C-Therm sensors work like yourhand, by rapidly determining the rateof heat flow from one material toanother. Like your hands, our sensorssupply the heat source and detectthe heat flow. They also have nosample size issues, and do notdestroy the sample being tested.

How Does It Work?

How it works: This approach isa transient technique that usesheat reflectance, similar to HotWire testing. The modification isthat the heating element issupported on a backing, thusallowing a one-directional heatflow. This allows the testing to benon-intrusive and permits thetesting of solids without the needto be melted. Therefore, thetemperature of the heatingelement versus the time functionis used to calculate the thermalconductivity and thermaleffusivity.

MODIFIED TRANSIENT PLANE SOURCE(MTPS)

How Does It Work?

Volta

ge (

but t

hink

Tem

pera

ture

)

Time

First 0.3 Seconds:Addressing ContactResistance,Non-Linear

0.3 – 0.8 Seconds:Within Sample, Linear

Which Is More Conductive?

Volta

ge (

but t

hink

Tem

pera

ture

)

Time

First 0.3 Seconds:Addressing ContactResistance,Non-Linear

0.3 – 0.8 Seconds:Within Sample, Linear

Option A

Option B

Easy Results

Thermal ConductivityThermal Effusivity

Temp.

Easily exportable to EXCEL™

APPLICATIONS:ENERGY MATERIALS

THERMAL CONDUCTIVITY OFMAGNESIUM HYDRIDEJACQUES HUOT 1 AND ADAM HARRIS*2,1 INSTITUT DE RECHERCHE SUR L’HYDROGÈNE, UNIVERSITÉDU QUÉBEC À TROIS-RIVIÈRES, QUÉBEC, CANADA2C-THERM TECHNOLOGIES, FREDERICTON, NEW BRUNSWICK,CANADANORTH AMERICAN THERMAL ANALYSIS SOCIETY (2010)

MAGNESIUM HYDRIDES

• Shows potential as a reversible"storage" medium for hydrogen whichhas led to interest in improving thehydrogenation and dehydrogenationreaction kinetics.

• Challenges:- High temperature of operation- Relatively slow kinetics- Cost ($)- Resistance to cycling- Heat transfer issues

HEAT TRANSFER ISSUES

• In the case of heat transfer, the problem isespecially significant because of the high heatof formation of magnesium hydride (75kJ/mol).

• Compounded by the fact that magnesium hasa low melting point.

• If heat is not transferred rapidly to some heatexchanger the magnesium inside the tank runsthe risk of melting during absorption (anexothermic process).

SAMPLE PREPARATION:BALL MILLING

A ball mill, a type of grinder, is acylindrical device used in grinding(or mixing) materials like ores,chemicals, ceramic raw materialsand paintsBall mills rotate arounda horizontal axis, partially filledwith the material to be groundplus the grindingmedium. Intensively used fordoping magnesium hydride withcatalysts

21

RESULTS

SEM

Scanning Electron Microscope (SEM) micrographs of powder MgH2 in the as-received state(A), after 10 hours milling (B), after 10 hours mill with 2% add of vanadium(C), and after 10hours mill with 2% add of V2O5(D)

RESULTS

23

RESULTS

Thermal conductivities as a function of relative density of MgH2 in the as-received state, after10 hours milling, after 10 hours mill with 2% add of vanadium, and after 10 hours mill with2at.% of V2O5.

CONCLUSIONS

• The effect of ball milling and catalyst additionon thermal conductivity of magnesium hydridein powder and compacted pellets wasinvestigated.

• Particle size has a big impact on thermalconductivity, smaller particles having thermalconductivity 33% lower than big particles.

• Compaction does not change this situationeven if densification is higher for powder withsmall particle size.

• A compound with big particles (20 μm andbigger) is preferable to small particle sizes.

NEXT STEPS?HIGH PRESSURE CELL (HPC)

©2013 C-Therm Technologies Ltd.

HIGH PRESSURE CELL (HPC)

1. Intermediate Flange2. Cover3. Eye Bolt4. Modified TCi Sensor5. Power Lead Gland6. Vessel7. Socket Head Cap Screw (Long)8. Socket Head Cap Screw9. Lock Pin10.Pressure In/Out Adaptor, with purge11.Thermocouple Adaptor12.Adaptor for TCi (cable feedthrough)


12

11

HPC CLOSED


HPC OPEN


THERMOELECTRICS

PERFORMANCEFigure of Merit: ZT (dimensionless)

WhereS = Seebeck Coefficient,

= electrical conductivityT = absolute temperatureλ = thermal conductivity

λThermal ConductivityPower Factor

Magnesium Silicide

THERMAL CONDUCTIVITY VS TEMPERATURE

R² = 0.9637

3.03.54.04.55.05.56.06.57.07.58.0

25 50 75 100 125 150 175 200

Ther

mal

Con

duct

ivity

(W/m

k)

Temperature (°C)

MgSi

PENG SHENGA,B, YIMENG SUNA,B, FEI JIAOA,B, CAIMING LIUA,WEI XUA,∗, DAOBEN ZHUA,∗ABEIJING NATIONAL LABORATORY FOR MOLECULAR SCIENCES,KEY LABORATORY OF ORGANIC SOLIDS, INSTITUTE OFCHEMISTRY, CHINESE ACADEMY OF SCIENCES, BEIJING100190,CHINA

BUNIVERSITY OF CHINESE ACADEMY OF SCIENCES, BEIJING100049, CHINA

OPTIMIZATION OF THE THERMOELECTRICPROPERTIES OFPOLY[CUX(CU-ETHYLENETETRATHIOLATE)]

CURRENT STUDY

poly(Cu-ethylenetetrathiolate)

Chosen because;• exhibit high room-temperature electrical

conductivities• Easy to synthesize• Researchers

previous experience

EQUIPMENT

• SB-100 Seebeck Measurement System (MMR Tech.)

• KEITHLEY 2002 Multimeter (Keithley Inst. Inc.)

• C-Therm TCi Thermal Conductivity Analyzer

THERMAL CONDUCTIVITIES

Oxidation

Reduction

Both oxidation and reduction decrease the thermal conductivity.However, the oxidation causes a greater decrease overallin the thermal conductivity measured with the TCi

DEEPA MADAN1,*, ZUOQIAN WANG1, ALIC CHEN1, PAUL K.WRIGHT1, JAMES W.EVANS2

1DEPARTMENT OF MECHANICAL ENGINEERING, UNIVERSITY OFCALIFORNIA, BERKELEY, CA 94720

2DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING,UNIVERSITY OF CALIFORNIA, BERKELEY,CA 94720

HIGH PERFORMANCE DISPENSER PRINTEDMA P-TYPE BI0.5SB1.5TE3 FLEXIBLETHERMOELECTRIC GENERATORSFOR POWERING WIRELESS SENSORNETWORKS

PROTOTYPE DEVICE

THERMAL CONDUCTIVITY

• The thermal conductivity ofconductivity of MABi0.5Sb1.5Te3 with 8 wt%extra Te dispensed printedfilm was 0.24 W/m-K.Lower thermal conductivityas compared to the bulk(1.1 W/m-K) is due to theinsulating nature of epoxy.

• Fine grain (5µm) activefiller particles also increasethe potential barrierscattering that contributesto lower thermalconductivity. 0

0.2

0.4

0.6

0.8

1

1.2

Bulk with 8 wt% extra Te

Thermal Conductivity (W/mK)

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Adam HarrisManaging DirectorC-Therm Technologies Ltd.

Email: [email protected]: +1 (506) 457 1515

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Characterizing Thermal Properties in Energy Research